Known from the state of the art are field devices, which serve for use in industrial plants. Such field devices have an often robust housing, in order to brave the environmental conditions of such applications.
Known from the state of the art is to provide the housing of a field device with an (Radio Frequency Identification) RFID data carrier, so that information stored in the RFID data carrier is contactlessly queryable. Furthermore, it is known from German Patent, DE 102008008072 A1 to connect these RFID data carriers with an internal electronics unit of the sensor, so that signals of the RFID data carrier can be provided internally to the sensor. To this end, the RFID-data carrier can be writable.
Furthermore, German Patent, DE 202006012632 U1 describes the application of RFID transponders for access control to a machine.
For wireless data transmission, moreover, different standards have been created. Thus, for example, an inductive coupling or near field coupling (NFC) (Near Field Communication) can occur via magnetic fields. Data transmission and often also energy supply occur, in such case, via a magnetic near field, which is mediated by coils in a reading device and in a so-called tag. The frequencies used in such transmission lie at 135 kHz, 13.56 MHz and are specified by the standards, ISO 18000-2 and ISO 18000-3, respectively ISO 22536 and ISO/IEC 15693. Furthermore, it is known to utilize electromagnetic dipole fields for remote coupling. In such case, the data transmission and often also the energy supply occurs via antennas, for example, dipole antennas or spiral antennas. The frequencies at which this coupling occurs lie at 433 MHz, 868 MHz and 2.45 GHz, which are specified by the standards, ISO 18000-7, ISO18000-6, respectively ISO 18000-4.
Conventional NFC communication in the peer to peer mode offers, however, the disadvantage that it is too power intensive for continuous bidirectional data transmission, such as occurs, for example, in the case of parametering a field device of process and/or automation technology via a software tool for field device configuration.
Furthermore, additionally known from the state of the art are fieldbusses and fieldbus systems as well as field devices for use in such fieldbusses. The field devices are supplied for this purpose with electrical energy via the fieldbus or via a separate energy source.
In such case, it is, on the one hand, disadvantageous that the power is limited via the fieldbus or in the field device, so that, for example, such as explained above, a continuous data transmission via a secondary interface is not possible. On the other hand, data cannot be exchanged with the field device, when its energy supply is interrupted.